1. Field of the Invention
This disclosure relates to handrails, in particular to systems, methods, and devices for quickly installing and removing handrails on walkways commonly used in construction and industrial facilities.
2. Description of the Related Art
Metal walkways are ubiquitous in industrial facilities and construction sites. These elevated platforms are used to quickly provide access to remote areas of a work site or to provide a bridge between two elevated areas.
These walkways are generally comprised of two side beams, often I-beams, arranged generally in parallel and connected at fixed intervals by crossbars to create an elongated rectangular grid of square openings. Metal grating placed in the openings provides a high-friction, low-slip surface for workers to walk on. A common technique is to use expanded metal grating with a high-friction texture on one side. These walkways are constructed of durable but relatively lightweight metals—often aluminum, carbon steel, or stainless steel—allowing them to withstand the rigors and stress of an industrial job site while still being inexpensive to transport, install, and take down.
Metal walkways are not without their shortcomings. For one, such walkways are often installed at heights far enough above the ground that if a worker slips or falls from the walkway, the impact may cause serious injury or death. Further, materials inadvertently kicked or dropped from such heights pose a serious risk of injury to those on the ground. In typical industrial applications, work materials and tools are usually heavy and, thus, are more likely to be dropped and more likely to cause serious harm. Further, workers hustling about a busy work site quickly become accustomed to navigating the metal walkways and gain confidence in its stability. As they become comfortable with the work site and move more quickly about the work site, they may tend to exercise less caution, which can increase the risk of a trip and fall. Further, as the work site becomes more congested with tools and materials, stray objects left on a walkway may pose an increased tripping hazard.
Injuries from workplace-related falls impose an enormous burden on the economy, as well as on employers, workers, and their families. In 2011, the Bureau of Labor Statistics reported that almost 30% of all workplace related injuries requiring days away from work were caused by the worker either falling or being struck by equipment, and laborers accounted for the highest proportion of injuries and illness in the private sector, experiencing such injuries at a rate three times greater than the private sector industry average, with a median recovery time of nine days. This problem is only exacerbated with respect to metal walkways, which are generally elevated and thus falls from them tend to be more dangerous.
Government regulations require safety handrails for walkways more than six feet above ground, but safety handrails are recommended for any application, no matter how low to the ground. Regardless, many walkways are manufactured without handrails, such as to make pieces more standardized, and there is no simple or effective way to secure handrails to such walkways. Because the sides of the walkway are generally comprised of metal beams, hardware cannot be quickly or easily attached to secure a safety handrail to the walkway. Further, permanently adding support for a handrail is often undesirable or impossible, such as where the walkways are leased, rented, or borrowed.
In many applications, safety handrails also need to be installed in unusual configurations, or in lengths not available in off-the-shelf products. Manufacturing custom metal handrails is time-consuming and expensive, and attaching them to the walkway can damage the walkway. Further, and as discussed, the crew may not be at liberty to modify the walkway in this fashion. Even where custom handrails are an option, there may not be enough time to craft and install them. Walkways are often erected on short notice, such as in an emergency situation, and the circumstances simply cannot wait for metal rails to be measured, cut, welded, and allowed to cool.
Further, custom metal handrails are expensive and once the job is completed, they generally can't be re-used, resulting in wasted time, money, and materials. Repairs to such handrails are also expensive and difficult, requiring a metalworker on site with access to proper metalworking tools and materials, who can cut metal to length and weld the pieces together. Metal is difficult, expensive, and time-consuming to work, often requiring specialized saw blades and dangerous tools such as high-temperature welding equipment. The repairs must also be given time to cool and bond, during which the walkway is less safe, and may be non-compliant with applicable safety regulations. Further, metal cuts leave sharp barbs which, if not filed, can snag clothing and cause injury to personnel and damage to equipment.
It is preferable to use cheaper and more flexible materials for custom handrails, such as wood. Wood is almost universally available at any job site, and milled boards come in a number of standard cuts. Most enterprises have at least one worker skilled in woodworking and the use of woodworking tools, and most enterprises have at least a basic set of wood cutting and shaping tools on site. Wood is easy, fast, and cheap to saw to length and attach, and can be quickly broken down and repurposed for other uses with minimum waste. Wood does not require dangerous welding equipment, and hardware joints needn't be given time to cure. Further, the ends of properly cut wood are generally smooth and can be made safe without extensive filing or sanding.
However, attaching a wooden handrail to a metal walkway is difficult. For walkways manufactured with receptacles for handrails, these receptacles are sized and shaped for metal handrails, which are generally round and, in any case, not sized to accept any standard size of milled lumber. Further, wood cannot be simply nailed or screwed to metal walkways using ordinary woodworking hardware because such hardware cannot penetrate metal. Special metalworking hardware is necessary, but such hardware is generally unsuitable for use with wood, and may cause splitting or splintering, reducing the integrity of the wood and comprising the stability of a handrail constructed therefrom. Further, walkways are often leased, rented, or borrowed and the crew is not at liberty to put holes into the walkways regardless, nor is it desirable to puncture holes in a metal walkway to attach a safety handrail. The stress placed on the handrail through ordinary use also would tend to weaken a hardware joint over time, wearing down the wood near the joinery until it splits or the hardware loosens and works its way out, causing the joinery to fail, the handrail to collapse, and defeating the purpose of erecting it.